Visit Macy's website
Once here, sign in (if you do not already have an account, you can continue shopping and checkout as a guest at the end)
Start your shopping, and go to your cart once you are ready. Once there, click on the box to Proceed to Checkout.
After entering your shipping information, you will move to the payment section. This is where you will enter your gift card details that were found within your confirmation email from Go365.